Red meat: the evidence

In last week’s newsletter, I said that I would be covering a couple of stories that emanated from the European Society of Cardiology conference, which was held in Munich between August 25th and August 29th. This story is more ‘inspired’ by the conference, rather than an ‘unpack’ of a conference presentation.

Do you remember the PURE study from September 2017? (Ref 1) We woke up to the headlines “Low-fat diets could increase the risk of an early death: Major study challenges decades of advice as it reveals fat has a PROTECTIVE effect”? (Ref 2) My Monday newsletter noted that PURE had the usual limitations of epidemiological studies – association not causation and relative vs. absolute risk – but it had none of the howlers of ‘that (not) low carb study’ from August 2018 (Ref 3). Being a truly global study, it also had some fascinating insights into characteristics beyond diet of the regions being compared.

One of the lead researchers for the PURE study, Dr Andrew Mente, presented further findings at the Munich conference. These were reported globally with headlines such as “Cheese and red meat are back on the menu after study suggests eating twice as much as officials advise” (Ref 4). “Eating cheese and red meat is actually good for you” (Ref 5). Mente and colleagues had found that consuming three portions of dairy and approximately one and a half portions of unprocessed red meat daily was associated with 25% lower rates of early death and 22% fewer heart attacks. Three portions of dairy could equate to two slices of cheese, 200ml of whole milk and 200ml of full-fat yoghurt. The red meat amount would be approximately 120-130g (4.5oz) daily, which would be a small steak. The red meat intake, which the PURE researchers found to be optimal, is almost double what public health advisors recommend.

This inspired me to share with you some evidence that I systematically reviewed in preparation for a presentation for the Sustainable Food Trust in November 2016. I have checked that the evidence has not been updated since my review. I was asked by the Sustainable Food Trust to present “A defence of red meat” at two meetings on the same day – one in London and one in Bristol. You can see the Bristol presentation here (Ref 6).

What I did

Since 1980, when the first “Dietary Guidelines for Americans” were published, other national dietary guidelines have been influenced by those in the US. The most recent Dietary Guidelines for Americans (2015) were published at the start of 2016. For my presentation in November 2016, therefore, the US evidence base was the natural place to start.

I reviewed the Nutrition Evidence Library, which was used by the Dietary Guidelines Advisory Committee (DGAC) for the 2015 revision (Refs 7, 8). The first interesting thing to note is that red meat was not documented as a category. Red meat appeared in a category called “animal protein.” The second interesting thing to note is that all data used for “animal protein” for the 2015 Dietary Guidelines for Americans came from 2010 i.e. nothing had been updated since the 2010 guidelines. One of the reasons Nina Teicholz works tirelessly for the US Dietary Guidelines to be evidence based is so that the committee will only make recommendations based on the current evidence.

Evidence: The totality of the evidence for CVD comprised seven articles – four of which were entirely about eggs – which represented prospective cohorts from the US and Japan published since 2000 (full references for each study can be found in Ref 8):

Five studies (i, ii, iv, v, vi) can be ignored immediately in an examination of red meat: four were entirely about eggs (none found any association with eggs and CVD) and the Halton study did not examine red meat.

vii) Sinha’s conclusion was: “Red and processed meat intakes were associated with a modest increase in risk of total mortality, cancer and CVD mortality in both men and women. In contrast, high white meat intake was associated with a small decrease in total and cancer mortality.”

Sinha’s definition of red meat was: “Red meat included all types of beef and pork and included bacon, beef, cold cuts, ham, hamburger, hot dogs, liver, pork, sausage, steak and meats in foods such as pizza and chilli.” Sinha did not study red meat, therefore.

BOTTOM LINE: Not one study has even evaluated red meat, let alone found any evidence against it.

2) What is the relationship between the intake of animal protein products and blood pressure?

Evidence: The totality of the evidence for type 2 diabetes comprised seven articles – prospective cohorts from the US published since 2000:

Four studies (i, iii, iv, vi) can be ignored immediately in an examination of red meat: one was entirely about eggs; two did not examine red meat and Van Dam found no association with red meat (even with hamburgers included).

One of Fung or Song should also be ignored as they were papers using the same data source: the Nurses’ Health Study.

ii) Fung’s conclusion was: “Positive associations were also observed between type 2 diabetes and red meat and other processed meats.”

Fung did not define red meat alone and the conclusion included processed meat.

The red meat definition in Song was ”Red meat intake was considered to be the sum of hamburger, beef, or lamb as a main dish, pork as a main dish, beef, pork, or lamb as a sandwich or mixed dish, and all processed meat.”

It is extremely likely that the Song definition of red meat is the same as for Fung, given that both papers were about the Nurses’ Health Study.

10 thoughts on “Red meat: the evidence”

Dr. Harcombe, I hope you are aware of a recent paper on this topic: Controversy on the correlation of red and processed meat consumption with colorectal cancer risk: an Asian perspective.https://www.ncbi.nlm.nih.gov/pubmed/29999423

The abstract pointed out that most studies on meat and colorectal cancer risk have ignored 2/3 of humanity and “Among 73 epidemiological studies, approximately 76% were conducted in Western countries, whereas only 15% of studies were conducted in Asia. Furthermore, most studies conducted in Asia showed that processed meat consumption is not related to the onset of cancer. Moreover, there have been no reports showing significant correlation between various factors that directly or indirectly affect colorectal cancer incidence, including processed meat products types, raw meat types, or cooking methods.”

So if you include Asians there’s no correlation — until those Asians emigrate and change to Western diets.

Hi Zoe, first of all let me reveal I am woeful at anything I. T. So if my question is about something you have cleat answered on this site sorry. Have you posted any data for meat and dairy consumption over the past years and decades? Or if not here is it in one, or more, of your books? Thanks

Most of the studies mention meat combined with grains and vegetables, such as pot pies, burgers, stews, lunch meat, hot dogs, meat puddings, and such. The most commonly eaten red meat is hamburger–how many people eat a burger without a bun, a soda, and a side of fries? I doubt they made any effort to separate the effects of the red meat alone.

Thanks for this article, Zoe! And thanks for making it available to everyone.

The testimonials from ex-vegans seem to be populating You Tube, and they are mostly unbelievable. The time frames seem to range from 1 to 20 years (Lierre Keith) until severe disease due to malnourishment occurs. The effects on children are especially tragic. Isn’t it way past time to start studying the health effects of an all-plant diet? In fact, why is meat consumption measured against plant consumption with the assumption that plants provide an optimal diet? If you look at the daily reported health tragedies due to veganism, even in children, perhaps it ought to be considered a public health concern.

The public health problem as it relates to nutrition has gotten so bad, a great many people are viewing it in terms of a conspiracy theory. sv3rge on You Tube is one such conspiracy theorist. He is doing a public service though in providing a platform for ex-vegans to tell their story. Here is one example of many, https://youtu.be/OAxQap0Rd0w.

My own view is that it is just another chapter in Charles Mackay’s book, written in the 19th century, “Extraordinay Popular Delusions and the Madness of Crowds.” Unfortunately it will take a number of generations to turn this around, if it gets turned around at all.